U.S. border officers aren’t allowed to look at any data stored only in the “cloud” — including social media data — when they search U.S. travelers’ phones, Customs and Border Protection acknowledged in a letter obtained Wednesday by NBC News.

The letter (PDF), sent in response to inquiries by Sen. Ron Wyden, D-Ore., and verified by Wyden’s office, not only states that CBP doesn’t search data stored only with remote cloud services, but also — apparently for the first time — declares that it doesn’t have that authority in the first place.

Read more on NBC. Cyrus Farivar of Ars Technica also covers the welcome news.